interestingly enough adding -lpangoft2-1.0 by hand to the end of the
link line seems to resolve it.

How about following?
% pkg-config --libs-only-l pangocairo
It should contain -lpangoft2-1.0, but probably not on your environment.
missing "pangoft2" in "Requires" for pangocairo.pc?

That definitely seems to be the issue:
-lpangocairo-1.0 -lpango-1.0 -lcairo -lgobject-2.0 -lgmodule-2.0
-lgthread-2.0 -lpthread -lrt -lglib-2.0
Added -lpangoft2-1.0 by hand to the end of pangocairo.pc allows the
build to run to completion, though this doesn't show as a problem on
NetBSD (tried with latest with pkgsrc)

I can reproduce this issue.
It probably came from deplibs_check_method of libtool.
libtool --config | grep deplibs_check_method
On Linux, "pass_all"
On NetBSD, "match_pattern /lib[^/]+(\\.so|_pic\\.a)\$"
If pango is rebuild with CONFIGURE_ARGS+=--enable-explicit-deps=yes,
This issue will be resolved.
--
OBATA Akio / obache%NetBSD.org@localhost